"Workers in the U.S. work more hours because unions here, which have become smaller and weaker have been unable to negotiate either a shorter work week, or higher real wages for 30 years," said Mike Olszanski, outreach coordinator in the Department of Labor Studies at Indiana School of Social Work. "Since wages are flat, the only way to earn more is to work more."

Ali R. Bustamante, an economic policy fellow in the Jesuit Social Research Institute at Loyola University New Orleans, told Wallethub: "Americans typically work more hours that workers in Europe, because American employment regulations promote greater working hours."